Actually, the problem is with alignment zones, as I haven’t specifically applied any hinting to the font. (Unless there is some output setting that does hinting automatically that I’m not aware of.)
Here’s the offending item. It’s printed on newsprint, 14 pt. The font is “.otf”, output to PDF from InDesign:

A Type 1 version of a very similar font (with almost the same alignment zones and standard stems) came out as intended.
This is on coated stock, again at 14 pt:

The main reason I give the fonts alignment zones is so that they are neat on screen:

Here is what the FontLab file looks like (a composite of screen grabs, actually):

Can anybody shed some light on my difficulty?